SB140 Schottky Diode 40V 1A DO-41 Equivalent & Substitute Parts

Part Overview

The SB140 is a through-hole Schottky rectifier diode manufactured by onsemi, rated for 40 V DC reverse voltage and 1 A average rectified current in a DO-41 axial package. The device is classified as obsolete, necessitating identification of active equivalent and substitute components for new designs and ongoing production requirements. Substitute parts must maintain electrical compatibility within the specified voltage, current, and thermal operating ranges while accommodating package and mounting variations.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) (Max)	40	V
Current - Average Rectified (Io)	1	A
Voltage - Forward (Vf) (Max) @ If	500 mV @ 1 A	mV
Speed	Fast Recovery ≤ 500ns, > 200mA (Io)	ns
Current - Reverse Leakage @ Vr	500 µA @ 40 V	µA
Capacitance @ Vr, F	110pF @ 4V, 1MHz	pF
Mounting Type	Through Hole	—
Package / Case	DO-204AL, DO-41, Axial	—
Operating Temperature - Junction	-60°C to 125°C	°C
Technology	Schottky	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the SB140 is determined by the following electrical and mechanical criteria:

Primary Substitution Criteria:

Voltage - DC Reverse (Vr) (Max): Must equal or exceed 40 V
Current - Average Rectified (Io): Must equal or exceed 1 A
Technology: Schottky rectifier diode
Mounting Type: Through Hole
Package / Case: DO-204AL, DO-41, or Axial compatible

Secondary Compatibility Factors:

Voltage - Forward (Vf) (Max) @ If: Lower or equal values preferred for efficiency
Current - Reverse Leakage @ Vr: Lower values preferred for leakage performance
Operating Temperature - Junction: Must accommodate application thermal requirements
RoHS and REACH compliance status for regulatory alignment

Substitute parts are grouped into two categories:

Direct Equivalents (40 V Rating): Parts with identical 40 V reverse voltage rating and 1 A current capacity, maintaining the same electrical performance envelope as the SB140.
Higher Voltage Alternatives (50 V Rating): Parts rated for 50 V reverse voltage with 1 A current capacity, providing enhanced voltage margin while maintaining current compatibility. These are suitable for applications where the additional voltage headroom does not create design conflicts.

Parameter Comparison

Part Number	Manufacturer	Vr (Max) [V]	Io [A]	Vf (Max) @ 1A [mV]	Ir @ Vr [µA]	Package	Product Status	RoHS Status
SB140	onsemi	40	1	500	500 @ 40V	DO-41	Obsolete	ROHS3 Compliant
SB140E-G	Comchip Technology	40	1	500	500 @ 40V	DO-41	Active	ROHS3 Compliant
1N5819G	Microchip Technology	40	1	600	1000 @ 40V	DO-41	Active	Not specified
1N5819RLG	onsemi	40	1	600	1000 @ 40V	Axial	Active	ROHS3 Compliant
10DQ04	SMC Diode Solutions	40	1	550	500 @ 40V	DO-41	Active	ROHS3 Compliant
1N5818-T	Diodes Incorporated	30	1	550	1000 @ 30V	DO-41	Active	ROHS3 Compliant
1N5819	Microchip Technology	45	1	490	50 @ 45V	DO-41	Active	Not specified
1N5819-1	Microchip Technology	45	1	340	50 @ 45V	DO-204AL	Active	RoHS non-compliant
MBR150G	onsemi	50	1	750	500 @ 50V	Axial	Obsolete	ROHS3 Compliant
MBR150RLG	onsemi	50	1	750	500 @ 50V	Axial	Active	ROHS3 Compliant

Engineering Selection Recommendations

Direct Equivalent Selection (40 V Rating):

The SB140E-G (Comchip Technology) is the primary direct equivalent, offering identical electrical specifications (40 V, 1 A, 500 mV forward voltage) in an active product status with ROHS3 compliance. This part maintains the same performance envelope as the SB140 and is suitable for direct substitution in existing designs.

The 10DQ04 (SMC Diode Solutions) provides an alternative 40 V, 1 A option with slightly elevated forward voltage (550 mV) and active product status. REACH compliance status differs from the SB140; verification against application requirements is necessary.

Higher Voltage Alternative Selection (45 V to 50 V Rating):

The 1N5819 (Microchip Technology) at 45 V rating provides enhanced voltage margin with superior reverse leakage performance (50 µA @ 45 V versus 500 µA @ 40 V) and lower forward voltage (490 mV). Active product status and widespread availability support long-term supply continuity.

The 1N5819RLG (onsemi) offers the same 40 V electrical performance as the SB140 in an axial package format with active status and ROHS3 compliance. Package format differs from the standard DO-41; mechanical fit verification is required.

The MBR150RLG (onsemi) at 50 V rating provides the highest voltage margin with active product status and ROHS3 compliance. Elevated forward voltage (750 mV) and higher reverse leakage (500 µA @ 50 V) must be evaluated against application thermal and efficiency constraints.

Parts Not Recommended for Direct Substitution:

The 1N5818-T (Diodes Incorporated) is rated for 30 V maximum reverse voltage, below the SB140 40 V specification. This part is suitable only for applications with reduced voltage requirements.

The 1N5819-1 (Microchip Technology) carries RoHS non-compliant status, limiting applicability in regulated environments requiring RoHS certification.

Frequently Asked Questions (FAQ)

Q: Can the SB140E-G directly replace the SB140 in existing circuit boards?

A: Yes. The SB140E-G maintains identical electrical specifications (40 V, 1 A, 500 mV forward voltage) and DO-41 package format. No circuit modifications are required. Both parts are ROHS3 compliant.

Q: What is the difference between DO-41 and Axial package formats?

A: Both formats are through-hole mounting styles for the same diode technology. DO-41 and Axial (DO-204AL) refer to the same physical package with identical lead spacing and hole diameter. Parts specified as "Axial" are functionally equivalent to DO-41 packages and are mechanically interchangeable.

Q: Why does the 1N5819 have a lower reverse leakage current (50 µA) compared to the SB140 (500 µA)?

A: Reverse leakage current varies with manufacturing process and die design. The 1N5819 exhibits superior leakage performance at its 45 V rating. Lower leakage reduces standby power dissipation and improves circuit efficiency in applications sensitive to reverse current.

Q: Can I use the MBR150RLG (50 V) instead of the SB140 (40 V)?

A: Yes, the MBR150RLG is electrically compatible. The higher 50 V rating provides additional voltage margin for transient protection. However, forward voltage is elevated to 750 mV (versus 500 mV for SB140), resulting in increased power dissipation. Thermal analysis is required to confirm acceptability in the target application.

Q: Is the 1N5818-T suitable as a substitute for the SB140?

A: The 1N5818-T is rated for 30 V maximum reverse voltage, below the SB140 specification of 40 V. This part is not suitable for direct substitution. Use only in applications with reduced voltage requirements below 30 V.

Q: What compliance certifications should I verify when selecting a substitute?

A: Verify ROHS3 compliance status and REACH classification against your application requirements. The SB140 is ROHS3 compliant and REACH unaffected. Most active substitutes maintain these certifications. The 1N5819-1 is RoHS non-compliant and unsuitable for regulated applications.

Q: How do I determine if a higher voltage-rated diode (45 V or 50 V) is acceptable in my circuit?

A: Higher voltage ratings provide enhanced transient protection and voltage margin. Verify that the elevated forward voltage drop does not exceed thermal dissipation limits. Compare power dissipation (P = Vf × I) across candidate parts. Confirm that reverse voltage transients in your circuit do not exceed the diode rating.

Q: Are there inventory or lead-time considerations when selecting substitutes?

A: Inventory levels vary by part and supplier. The 1N5819RLG shows high availability (300,400 pcs), while the SB140E-G has moderate availability (4,723 pcs). Verify current stock status with your component supplier for production planning.

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